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Author: Subject: Removed valve guides

posted on 20/11/17 at 06:55 AM Reply With Quote
Removed valve guides

I have just removed the valve guides.
Used a valve guide removal tool and a hammer.

I know you should not hammer them out but press them but them came out easy enough

The limit is 1 tonne on this head so was surprised how easy it was. Once you get them moved 1mm they they come out okay.

The inlets were easier than the exhaust, this is because the heat in the exhaust caused the bronze guides to expand in the aluminium head and when they contract the bronze resists this.

Anyway once I got the Bronze guides out I noticed the holes in the exhaust has just that bit extra movement in them when wobbling the drift tool.

I then thought put one of the OLD guides back in one of the exhaust hole and see how it holds.

It went in easier then I got it out but I again at to use a hammer just to tap it back in.
Please note it was not loose!!!

I would say they will all be fine. My question is once i get the engine running the exhaust heat will cause the head to expand as well as the bronze but aluminium expands at a quicker rate.

Once it contracts a few times I think it will be good to go.

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posted on 20/11/17 at 02:55 PM Reply With Quote
Bronze guides should no be forced into the head you use the hot and cold method to install them
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posted on 20/11/17 at 04:40 PM Reply With Quote
I will on the inlet size. On the exhaust they do tap in okay.

I noticed a slight score in one of the holes. I would like to fill that. I know loctite is not a good method.

You want the fullest of heat transfer from the bronze guide to the head.

Can I smear some aluminium epoxy to fill the score (scratch).

1200Celcius protection

Please note this is not to hold any part of the guide but to fill a score/scratch to smoothen it.

Pretty sure oil will not leak as it is but want to be 100% certain.

Again the guides are not loose at all on the exhaust side. I am just surprised how easily they can go on with a tap of a hammer. These were of course the old guides I tested back in.

New ones are on the way.

[Edited on 20/11/17 by bikecarbfred]

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